Assuming Nacho takes the aggressive route while trying to find out, he'll find the merchant assistants tight lipped and quick to double down that they would never commit such heinous activity.

If he's sweeter about it, or perhaps pretends he's a fellow merchant looking to understand how much he can get away with while practising his trade, they'll admit to it and say that former Regent Thyvault is fully aware of the trickery, but accepts the deliveries without fuss. It is 'sanctioned.'